This invention relates generally to medical catheters and, more particularly, to methods for steering, or guiding, medical catheters through body tissue.
Atherosclerotic plaque is known to build up on the walls of arteries in the human body. Such plaque build up restricts circulation and often causes cardiovascular problems, especially when the build up occurs in coronary arteries. Accordingly, it is desirable to remove or otherwise reduce plaque build up.
Known catheters implement laser energy to remove plaque build up on artery walls. One known catheter includes a laser source and a catheter body. The catheter body has a first end and a second end, or head, and several optical fibers extend between the first end and the second end. The laser source is coupled to each of the optical fibers adjacent the catheter body first end and is configured to transmit laser energy simultaneously through the optical fibers.
To remove arterial plaque, for example, the catheter body is positioned in the artery so that the second end of the catheter body is adjacent a region of plaque build-up. The laser source is then energized so that laser energy travels through each of the optical fibers and substantially photoablates the plaque adjacent the second end of the catheter body. The catheter body is then advanced through the region to photoablate the plaque in such region.
While known laser catheters are generally acceptable in connection with removing plaque from a straight region of plaque build-up, such catheters are not optimal in connection with curved regions of plaque build-up. While advancing the energized laser catheter in the curved region, it is possible for the second end of the catheter body to contact the arterial wall adjacent the curve, which may result in perforation of the arterial wall.
Until now, it was believed that a guide wire must be used to facilitate steering a catheter through a curved region of plaque build-up without perforating the arterial wall. Particularly, a guide wire is advanced through the artery and region of plaque build-up so that it forms a path through the artery and plaque build-up. The catheter is then guided through the artery using, the guide wire.
While guide wires facilitate steering catheters through curved regions of plaque build-up, inserting guide wires is time consuming and tedious. In addition, it often is not feasible to insert a guide wire into an artery. For example, a guide wire typically can not be inserted into a totally occluded artery, which results in subjecting a patient to bypass surgery.
Accordingly, it would be desirable to provide a catheter which may be advanced through a curved region of plaque build-up without requiring a guide wire. It also would be desirable to provide such a catheter which may be advanced through a totally occluded artery by removing plaque in such region.
These and other objects are attained by an catheter which, in one embodiment, includes a catheter body having a first group of optic fibers and a second group of optic fibers. The first group of optic fibers is adjacent the second group of optic fibers, and each group of optic fibers includes at least one optic fiber having a first end and a second end. The second ends of the optic fibers form a substantially rounded and self-centering catheter head.
A control element is communicatively coupled to the first ends of the respective optic fibers and is configured to transmit energy through the optic fibers of each respective group. Particularly, the control element is configured to selectively transmit energy through either the first group of optic, fibers, or the second group of optic fibers, or both the first and second groups of optic fibers simultaneously.
The catheter is inserted into a body passage, e.g., an artery or other blood vessel, and advanced until the catheter head is adjacent a region of blockage, e.g., a region of plaque build-up. The catheter is then advanced through the region of blockage by selectively energizing one of the groups of optic fibers or both of the groups of optic fibers. Particularly, while the region of blockage is substantially straight, the catheter is advanced while the control element transmits energy through both the first and second groups of optic fibers to photoablate the blockage adjacent the catheter head. While the region of blockage is curved, for example, so that the arterial wall is adjacent the first group of optic fibers, however, the control element transmits energy solely through the second group of optic fibers. Alternatively, while the region of blockage is curved so that the arterial wall is adjacent the second group of optic fibers, the control element transmits energy only through the first group of optic fibers. Accordingly, while advancing the advancing catheter through a curved region, the catheter only photoablates blockage adjacent the respective energized group of fibers, e.g., blockage away from the arterial wall, to form a path through such blockage and the self-centering head facilitates maneuvering the head along such path.
The above-described catheter may be advanced through a curved region without requiring a guide wire. Such catheter also may be advanced through a totally occluded artery by removing plaque in the blockage region.